Field of the Invention
The present invention relates to an electrophotographic image forming apparatus (also referred to as an “image forming apparatus”), and to a cartridge detachably mounted to the apparatus main unit of the image forming apparatus.
An image forming apparatus forms images on a recording medium using an electrophotographic image forming process. Examples of image forming apparatuses include electrophotographic copiers, electrophotographic printers (e.g., laser beam printers, LED printers, etc.), facsimile apparatuses, word processors, and so forth.
A cartridge is an arrangement where at least one of an electrophotographic photosensitive drum (also referred to as “photosensitive drum”) that is an image bearing member and a process unit (e.g., developing agent bearing member (also referred to as “developing roller”)) that acts upon the photosensitive drum has been formed into a cartridge. The cartridge is detachably mounted to the image forming apparatus. Both the photosensitive drum and the developing roller may be integrally formed into a single cartridge, or separately formed as different cartridges. The former, where both the photosensitive drum and developing roller are included, is referred to as a “process cartridge. In the latter, the arrangement including the photosensitive drum is referred to as a “drum cartridge”, and the arrangement including the developing roller is referred to as a “developing cartridge”. The term “image forming apparatus main unit” refers to the remainder of the image forming apparatus after removal of the cartridge(s).
Description of the Related Art
Conventionally, image forming apparatuses have used the cartridge system where process cartridges, drum cartridges, and developing cartridges are detachably mounted to the main unit of the image forming apparatus. According to these cartridge systems, maintenance of the image forming apparatus can be performed by the user him/herself, without having to depend on a field engineer for service, which has markedly improved ease of use. Accordingly, these cartridge systems are in widespread use in image forming apparatuses.
Positioning portions are provided to the cartridge, to position the cartridge in the image forming apparatus. There also are provided cartridges having memory for communicating with a power supply portion that supplies power from the image forming apparatus and with the image forming apparatus to record information of the cartridge, in order to control the image forming process (e.g., Japanese Patent Laid-Open No. 2014-119505).
The positions of a process unit and electric contacts provided to the cartridge, serving as an interface portion with the image forming apparatus are preferably highly precise, from the perspective of image quality stability and reducing the size of the image forming apparatus and cartridge. For example, the cartridge includes the photosensitive drum, and multiple electric communication units such as electric contacts and memory, as interface portions with the image forming apparatus.
Inside the main unit of the apparatus the cartridge is positioned by being pressed upwards by a cartridge lifter provided to the main unit of the apparatus so as to press the cartridge against an abutment portion of a deep-side frame. A positioned portion provided to the cartridge, that is abutted against the deep-side frame by being pressed upwards is provided near the photosensitive drum. That is to say, the positioning portion is at a position away from the electric contacts and memory. This tends to result in larger error in the position of the electric contacts and memory within the main unit of the apparatus. Conventionally, stable electric communication has been realized by forming a mechanism that can follow positional error of the electric contacts of the cartridge. This has been performed by managing the dimensions of parts making of the cartridge at a high level of precision, and forming units of multiple parts at the electric contact portion of the main unit of the apparatus.